Total Tree Biomass Research Articles

Allometry and partitioning of above- and below-ground biomass in farmed eucalyptus species dominant in Western Kenyan agricultural landscapes

Farmers in developing countries are one of the world's largest and most efficient producers of sequestered carbon. However, measuring, monitoring and verifying how much carbon trees in smallholder farms are removing from the atmosphere has remained a great challenge in developing nations. Devising a reliable way for measuring carbon associated with trees in agricultural landscapes is essential for helping smallholder farmers benefit from emerging carbon markets. This study aimed to develop biomass equations specific to dominant eucalyptus species found in agricultural landscapes in Western Kenya. Allometric relationships were developed by regressing diameter at breast height (DBH) alone or DBH in combination with height, wood density or crown area against the biomass of 48 trees destructively sampled from a 100 km2 site. DBH alone was a significant predictor variable and estimated aboveground biomass (AGB) with over 95% accuracy. The stems, branches and leaves formed up to 74, 22 and 4% of AGB, respectively, while belowground biomass (BGB) of the harvested trees accounted for 21% of the total tree biomass, yielding an overall root-to-shoot ratio (RS) of 0.27, which varied across tree size. Total tree biomass held in live Eucalyptus trees was estimated to be 24.4 ± 0.01 Mg ha−1, equivalent to 11.7 ± 0.01 Mg of carbon per hectare. The equations presented provide useful tools for estimating tree carbon stocks of Eucalyptus in agricultural landscapes for bio-energy and carbon accounting. These equations can be applied to Eucalyptus in most agricultural systems with similar agro-ecological settings where tree growth parameters would fall within ranges comparable to the sampled population.

Biomass and carbon storage in an age-sequence of Japanese red pine (Pinus densiflora) forests in central Korea

The biomass and carbon (C) storage of the main ecosystem components were examined in an age-sequence of six Japanese red pine forest stands in central Korea. The tree biomass was determined by the destructive method, and the C storage of the tree biomass, forest floor and mineral soil was estimated by analyzing the C concentration of each component. The above-ground and total tree biomass increased from 21.76 and 28.82 Mg ha−1 in the 17-year-old stand to 308.83 and 385.74 Mg ha−1 in the 73-year-old stand. The comparisons of above-ground tree and tree root biomass in replicate stands indicated that stand density has an effect on tree biomass partitioning for Japanese red pine, especially on the biomass allocation of above-ground tree and tree roots. The C concentrations were lowest in the tree roots while the highest concentrations were found in the foliage across the six Japanese red pine forest stands. The C storage in the forest floor and mineral soil were age-independent. The above-ground and total ecosystem C stocks increased from 19.40 and 43.49 Mg ha−1 in the 17-year-old stand to 162.72 and 247.39 Mg ha−1 in the 73-year-old stand. Although the total tree biomass C showed considerable accumulation with stand age, the relative contribution of the below-ground ecosystem to the total ecosystem C storage demonstrated large variation. The results of this study assist in understanding C storage and its change with stand development in Japanese red pine forests, which makes this species a large sink for atmospheric C at the regional scale.

Biomass and Carbon Storage Pattern in an Age Series of Teak Plantation in Dry Tropics

The present study was conducted to investigate the biomass and carbon storage pattern in an age series of teak plantation in tropical environment at Barnawapara Wildlife Sanctuary in Raipur district of Chhattisgarh during the year 2011–2012. The study was conducted in three different age of plantation (19 years, 23 years and 33 years old) in tropical environment. Forest structure was determined using phytosociological observations. Biomass for each plantation site was estimated using allometric equations based on the relationship between girth of tree and dry weight of the components. The carbon storage for the vegetation components was computed as the sum of the products obtained by multiplying dry weights of components with their mean carbon concentrations. A total of 13 species of 9 families were encountered. Tree stand density varied from 1010–1380 stems ha−1 with basal area ranging from 23.54 to 44.75 m2 ha−1. Species diversity index varied between 0.24 for 19 years old teak plantation to 1.07 for 33 years old teak plantation. The total biomass recorded in age series of teak plantation was between 119.37 t ha−1 and 235.14 t ha−1, and it was highest in 33 years old teak plantation followed by 23 years old teak plantation and lowest in 19 years old teak plantation. The total above ground biomass in different age of plantation ranged from 99.08 to 197.88 t ha−1. The below ground biomass in different plantation sites varied from 20.29 to 37.26 t ha −1. The total tree biomass increased with age of the plantation. The total carbon (t ha−1) recorded among the different age of plantation sites was maximum in 33 years old teak plantation (101.40) followed by 23 years old teak plantation (90.66) and 19 years old teak plantation (51.32). The higher proportion of above ground carbon was allocated in bole followed by branch and root in different age of plantation. The above ground carbon in different age of plantation ranged between 44.07 to 88.09 t ha−1. The below ground carbon in different plantation varied from 7.25 to 13.31 t ha−1. From these studies, it is evident that the biomass and carbon increased steadily with respect to the increase in the age, dbh and height of the plantation as the biomass is generally associated with the age and size of the trees. Biomass of the individual tree components also increased with the increase in the age of the plantation.

Ecosystem respiration and tree growth influenced by thinning in a red pine forest in southern Korea

This study was conducted to determine the effect of thinning on the ecosystem respiration in a red pine forest in southern Korea. We measured the ecosystem respiration and its component respirations from soil, stem, leaf, and coarse woody debris (CWD) in thinned and control stands during 2010. The forest was thinned in October 2009. The total respiration was 8.37 and 8.82 Mg C ha−1 year−1 in the thinned and control stands, respectively. Estimated annual soil, leaf, stem, and CWD respirations in the thinned stand were 5.55, 1.41, 0.90, and 0.51 Mg C ha−1 year−1, accounting for 66, 17, 11, and 6%, respectively. Estimated annual soil, leaf, and stem respirations in the control stand were 5.54, 2.09, and 1.19 Mg C ha−1 year−1, accounting for 63, 24, and 13%, respectively. The organic C storage in tree biomass (149.24 vs. 198.61 Mg C ha−1), input from litterfall (6.79 vs. 7.92 Mg dw ha−1 year−1) and total tree biomass increment (7.67 vs. 9.28 Mg C ha−1 year−1) were all significantly lower (P < 0.05) in the thinned stand than in the control stand. However, the individual tree increment was higher in the thinned stand than in the control stand (9.35 vs. 8.24 kg C year−1). Organic C output through the loss rate of litter mass was significantly higher (55 vs. 50%, P < 0.05) in the thinned stand than in the control stand. These results indicate that ecosystem respiration was slightly increased by thinning, whereas tree biomass C dynamics, and organic C input and output through litter production and decomposition were decreased by thinning. Further long-term study and analyses will be required to define overall C cycling in red pine forests.

Quantification of Potential Lignocellulosic Biomass in Fruit Trees Grown in Mediterranean Regions

This research was based on three species: Citrus sinensis (orange), Olea europaea (olive), and Prunus amygdalus (almond). The biomass was determined for a complete tree without roots, but including stem, branches, and canopy or crown. The obtained results demonstrate that the stem volume is slightly higher for almond trees (0.035 m3/tree) than for olive trees (0.027 m3/tree). In comparison, the average stem volume of orange trees is lower (0.006 m3/tree). On the other hand, the total biomass volume including canopy branches is similar in all three species: 0.043 m3/tree for orange tree, 0.066 m3/tree for olive tree, and 0.040 m3/tree for almond tree. The new practical quantification model for these Mediterranean agricultural crops is based on total biomass calculations normally used in forestry stands. So, the obtained values were used to develop models for biomass of the stem, branches, and canopy, relating them with the diameter and volume stem. The regression analysis shows a significant correlation with minimized estimation errors. This allows a practical use of this model in biomass calculation in standing trees, both for total tree biomass and also for pruning material.

Impact of fertilizer-water management on nitrogen use efficiency and potential nitrate leaching in citrus trees

In citrus production, the combination of adequate irrigation and nitrogen (N) management is considered a key factor in improving N uptake efficiency, so as to minimize nitrate () leaching below the root zone and maintain optimal crop yield. The response of eight-year-old citrus trees grown in lysimeters to two combinations of fertilizer and water management techniques – split N application in drip irrigation (DI-F) vs. a single broadcast application with flood irrigation (FI-B) – was compared by means of the use of a 15N-labeled fertilizer (ammonium nitrate). Soil sampling 54, 116, 175 and 238 days after the beginning of the experiment and destructive harvest of trees at the end of the growing cycle allowed the determination of the fate of the labeled fertilizer supplied. The 15N recovered in the different compartments of the plant-soil system and fertilizer nitrogen uptake efficiency (FNUE, 15N taken up by the plant per 15N supplied) was also quantified. Irrigation-fertilizer management practices had no effect on either total tree biomass or in fruit yield; however, a significantly greater development of coarse roots in the DI-F treatment was recorded. Fertilizer-N uptake was 25% higher in trees in the DI-F than in the FI-B treatment; fine roots and fruits of DI-F trees accumulated 2.1- and 1.4-fold higher fertilizer-N, respectively, compared to the corresponding organs of FI-B trees. At the end of the experiment, -15N concentrations in the 0–20 cm and 60–90 cm layers of DI-F trees were higher than those in FI-B trees, whereas no differences were recorded for -15N concentrations of both treatments. Potential nitrate leaching (PNL) 54 days after the beginning of the experiment represented 8% of fertilizer-15N delivered in FI-B, whereas in DI-F it was almost negligible. In DI-F trees, PNL become noticeable on day 175, highlighting the effect of this irrigation method in reducing and slowing down the movement through the soil profile. At the end of the experiment PNL represented 14% and 5% of fertilizer supplied for FI-B and DI-F, respectively. FNUE was significantly higher (12%) with the DI-F treatment when compared to FI-B treated trees. Comparison of the two water-fertilizer management practices studied in the present work allowed us to conclude that the DI-F treatment increased FNUE while diminishing nitrate leaching, when compared to the FI-B treatment.

Post-fire vegetation response as a proxy to quantify the magnitude of burn severity in tropical peatland

In recent years, fires in tropical forests in Southeast Asia have become more frequent and widespread, resulting in an increased need to evaluate fire impacts at a landscape scale. We examine whether post-fire vegetation regrowth can be used as a proxy to evaluate burn severity in a peatland landscape in Central Kalimantan, Indonesian Borneo, that has been subject to frequent fires. Several single- and bi-temporal indices as well as spectral fraction endmembers derived from either a post-fire image or a combination of pre- and post-fire images obtained by the Landsat sensor were examined. Spectral data were correlated with vegetation variables obtained from in situ measurements collected 4 years after the last fire. Of the tested spectral data, the bi-temporal and single normalized burn ratio (dNBR and NBR) showed the strongest correlations with the sets of vegetation variables (i.e. total woody aboveground biomass, tree density, and number of trees <10 cm diameter at breast height (DBH)). The results of an analysis of variance (ANOVA) and Tukey's multiple comparison of means test confirmed that NBR, dNBR, and the normalized difference water index could delineate four regrowth classes, thus confirming their utility in separating areas subjected to a single fire from those affected by multiple fires (MFs) as well as for discrimination between fires of differing severity. The results (a) provide evidence of the long-lasting impact that MFs have on forest recovery in this ecosystem and (b) confirm that vegetation response can be used as a proxy to quantify burn severity in locations affected by MFs.

Developing contemporary and historical live tree biomass estimates for old pine-hardwood stands of the Midsouth, USA

Calculating stand biomass potential is an increasingly important aspect of silviculture, particularly when attempting to restore forest ecosystems or determining additionality in sequestered carbon. However, the lumbering of the original forests of the Midsouth region of the United States of America, coupled with the accelerating conversion of unmanaged natural-origin stands to loblolly pine (Pinus taeda L.) plantations, make quantifying historic biomass difficult. If carefully done, it is possible to estimate presettlement biomass from past references and modern-day old pine-hardwood remnants. Pine sawtimber-only volume estimates from old reports indicated low biomass in the virgin pine-dominated forests of the Midsouth, from as little as 10–14Mg/ha up to 72Mg/ha. Given the incompleteness of these lumber yield-only data, a set of more detailed stand table-based historic descriptions were then coupled in this study with modern allometric equations to produce more complete estimates of biomass. These suggested that presettlement pine-hardwood stands of this region averaged ∼112Mg/ha in total (above- and below-ground) live tree biomass (range=54–171Mg/ha; n=6 stands). Contemporary old forests are considerably better stocked, with an estimated 224–318Mg/ha (n=6 stands). Individual loblolly pines from the historic period reached 183cm in diameter and may have had as much as 32Mg of biomass, though specimens <6Mg were considerably more common. Large individual tree values but low stand levels imply disturbance (especially fire) regulated total tree biomass in historic forests of the Midsouth. These results further indicate that extensive restoration of modern unmanaged forests to past stand structures will likely decrease regional biomass.

Pattern of carbon allocation across three different stages of stand development of a Chinese pine (Pinus tabulaeformis) forest

AbstractThe pattern of carbon (C) allocation across different stages of stand development of Chinese pine (Pinus tabulaeformis) forests is poorly documented. In order to understand the effects of stand age on the C pool of the Chinese pine forest ecosystem, we have examined the above‐ and belowground C pools in three differently aged stands of Chinese pine in the northern mountains of Beijing, China, by plot‐level inventories and destructive sampling. Our results suggest that tree branch and foliage biomass should be estimated by age‐specific equations. Reasonably accurate estimates of tree stem, tree root, aboveground, and total tree biomass in a Chinese pine forest at different development stages were obtained using age‐independent allometric equations from tree diameter only. The ratio of belowground to aboveground tree biomass was relatively constant with stand aging, remaining around 21 %. The contribution of aboveground tree biomass C increased from 21 % of the total ecosystem C in a 25‐year‐old stand to 44 % in a 65‐year‐old stand, subsequently falling to 41 % in a 105‐year‐old stand, while the contribution of mineral soil C decreased from 64 % of the total ecosystem C in 25‐year‐old stand to 38 % in a 65‐year‐old stand, subsequently increasing to 41 % in a 105‐year‐old stand. The C stock of the total ecosystem and its aboveground tree, tree root, forest floor, and mineral soil components continuously increased with stand ageing, whereas the C stock of the understory showed a declining trend and contributed little to the total site C pool.

Allometric equations for estimating biomass in agricultural landscapes: II. Belowground biomass

The high heterogeneity and diverse management effects on trees in agricultural landscapes limit the use of standard allometric equations developed for forests; hence the need to develop robust allometric equations and root:shoot ratios (RS) for more accurate estimation of belowground biomass. Local generic equations were developed from 72 trees (diameter at breast height (dbh): 3–102cm) destructively sampled across three 100km2 benchmark sites in Western Kenya. Belowground biomass of the harvested trees accounted for about 20% of the total tree biomass; yielding an overall RS of 0.26, which varied across an altitudinal and precipitation gradient. The equation based on dbh alone estimated belowground biomass carbon in agricultural mosaics of Western Kenya to be 5±0.01MgCha−1 with about 90% accuracy. Two of the equations recommended for tropical species produced estimates that were about 35 and 21% lower. The equation with dbh as predictor is therefore reliable for estimating belowground biomass in agricultural landscapes while RS should be used with great care depending on soil and management conditions as shown by the great variability among the blocks evaluated. Equations presented in this study will significantly improve the accuracy of root biomass estimates in agricultural landscape mosaics without the high investments in excavating the root system.

Influence of time since fire on pinyon–juniper woodland structure

Although development of pinyon–juniper woodlands is understood to require decades after stand-replacing fire, data describing relationships between many key structural elements and time since fire (TSF) are lacking. In this study, we sampled live trees, seedlings, shrubs, snags, and downed logs on 13 sites that together comprised a 370-year fire chronosequence. We analyzed individual relationships between structural attributes and TSF. We also developed an additive index of structural complexity and analyzed its relationship with TSF. Live juniper and total tree density were positively and linearly related to TSF (R2=0.76 and 0.49, respectively). Pinyon tree density and TSF were not significantly related. No live trees (⩾1.37m height) were found on sites burned less than 30years before sampling, although seedlings were found as early as 6years TSF. Live pinyon tree biomass, live juniper biomass, and total tree biomass followed “s-shaped” functions (4-parameter Weibull; R2=0.32, 0.62, and 0.96, respectively), with total biomass maximizing at 65Mgha−1 around 250years since fire. Seedling densities and shrub cover were not significantly related to TSF. Juniper snag density showed a significant negative relationship with TSF (R2=0.54) and total snag density followed a “u-shaped” function depending on TSF (2nd-order polynomial; R2=0.47). Pinyon snag density and TSF were not significantly related. Density of rotten logs was positively and linearly related to TSF (R2=0.46) whereas sound logs and TSF were not statistically related. Structural complexity showed a positive linear relationship with TSF (R2=0.46). These results indicate that although individual structural elements show various relationships with TSF, structural complexity increases as sites approach persistent woodland conditions. Findings from this study provide resource professionals with information that can help in developing and assessing management approaches intended to emulate natural structural patterns.

Characterization of the effects of inter-tree competition on source–sink balance in Chinese pine trees with the GreenLab model

We investigate the characteristics of individual tree response to competition on source–sink balance through the functional–structural plant model GreenLab. Four Chinese pine (Pinus tabulaeformis Carr.) trees were destructively sampled and were divided into two groups: high-density group and low-density group. First, the effects of density on organ dimensions and on organ relative mass were analysed based on experimental measurements. These were primary indicators of the plant response to competition. Second, the hidden parameters of the GreenLab model, as well as a tree-specific characteristic surface, were estimated using the data of total tree biomass for needle and wood compartments, for each of the four trees in parallel. The quality of the fitting is finally validated using data of individual organ mass at shoot level for the sampled branches. The Mann–Whitney Student’s t test showed that there were significant differences between the shoot attributes of the two groups for shoot diameter, shoot biomass and needle biomass. No significant difference was found for current year shoot lengths of the two groups. The parametric identification of the model allowed estimating and comparing the amount of biomass that was allocated to primary growth and to secondary growth in the two density conditions. It showed that biomass allocated to secondary growth (ring compartment) was the most strongly affected by density, and that the organ demand satisfaction ratio profiles of each of these trees were a relevant, integrated indicator of the tree state.

Modelling dry matter allocation within Alnus nepalensis D. Don trees in Nepal

The models describing dry matter partitioning and allocation to various components within the individual trees would be important inputs for process-based individual tree growth models and simulation systems. This study presents the allometric and quadratic models fitted to the ratios of biomass data of various components (leaf, branch, stem, and root) of the individual tree against diameter at breast height (dbh). Data from twenty-seven Alnus nepalensis trees in mid-hill region of Nepal were used to develop the models. The most attractive fit statistics were found with the model of ratio of stem to leaf biomass (R2 = 0.95), and similarly the models with the ratios of leaf to branch, leaf to above-ground, and leaf to total-tree biomass explained more than 90% variations. The results also showed that leaf, branch, above-ground and tree-total biomass amounts rapidly increased with increasing dbh. The ratios of leaf to branch, leaf to above-ground, leaf to total-tree, crown to total-tree, and root to total-tree biomass rapidly decreased with increasing dbh in earlier stage and gradually levelled off in the later stage. The models can be used for estimation of biomass of components of the individual tree. These models may also be useful inputs for process-based individual tree growth models which have been gaining the popularity in forest science in recent years. Key words: Alnus nepalensis, biomass model, biomass ratio, dry matter allocation, Nepal.

Individual biomass and carbon equations for Mimosa scabrella Benth. (bracatinga) in southern Brazil

Mimosa scabrella Benth. is an important native species of southern Brazil widely used for energy and promising for reforestation carbon offsets. Quantification of biomass and carbon stock is valuable for both purposes. From a forest inventory conducted in southern Brazil, data of M. scabrella were analyzed. Thirty sample trees were felled, excavated and weighed in the field and brought to laboratory for biomass and carbon determination. The total aboveground biomass represented 85% of the tree biomass, while roots corresponded to 15%. Correlation matrix of diameter at 1.3 m height (D), tree height (H) versus total and compartment biomass (P) indicated strong association between tree dimensions and biomasses. Five regression models were tested and equations were fitted to data of five biomass compartments and total tree biomass. The best fitting model for total biomass was P = –0.49361 + 0.034865 x DH whereas for the partial biomass of the compartments was lnP = β + β x ln(D) + β lnH. Carbon concentration was statistically significantly different in foliage than in other compartments. Three approaches of calculating carbon stocks were evaluated and compared to actual data: 1) Estimated total biomass x weighted mean carbon concentration; 2) Estimated partial (compartment) biomass x compartment average carbon concentration; and 3) Carbon regression equations. No statistical difference was detected among them. It was concluded that biomass equations fitted in this study were accurate and useful for fuelwood and carbon estimations.2012

Biomass, basic density and biomass expansion factor functions for European beech (Fagus sylvatica L.) in Denmark

The objective of this study was to analyse the within-tree allocation of biomass and to develop biomass functions for above- and below-ground components of European beech in Denmark. Separate functions were developed for stem, branches, below-ground stump and root system, total above-ground biomass and total tree biomass. For each of these components or aggregate components, models were also developed for the average basic density of wood and bark. To enhance the versatility of the models, a function for estimating the biomass expansion factor (BEF) was also developed. The functions were based on 66 trees measured for total biomass. Model performance was evaluated based on 74 trees measured only for above-ground biomass. The trees were sampled in 18 different forest stands covering a wide range of tree sizes and stand treatments. Models were estimated using a linear mixed-effects procedure to account for within-stand correlations. The functions for biomass and BEFs included only diameter at breast height and total tree height for individual trees as predictor variables. Inclusion of additional variables reflecting site quality or stand density did not improve model performance. The functions for basic density included individual tree diameter, tree height and quadratic mean diameter as predictor variables, indicating an effect of stand density on the basic density of wood and bark.

Estimation of Above Ground Tree Biomass and Carbon of Pinus caribaea (Morelet)

Forests in Sri Lanka contribute to the mitigation of global climate change through sequestrating a net amount of carbon dioxide and also maintaining carbon stocks as forest biomass. This study was conducted using an empirical method to understand the biomass and stored carbon by forest plantations in Sri Lanka. Further, in this study, the possibility of predicting the above ground tree biomass and carbon of Pinus caribaea (Morelet) was investigated. A 27 year old P. caribaea plantation was selected from the Low Country Wet Zone in Sri Lanka and the data were collected using 0.05 ha sample plots. Without felling trees, a core sample was obtained from the stem and biomass and carbon of that sample was used to estimate the stem biomass and carbon through volume measurements. The canopy biomass and carbon were estimated using samples of primary, secondary and tertiary branches and leaves. The total above ground tree biomass and carbon were estimated by adding the stem and canopy values together.It was found that, for 27 year old P. caribaea, the average above ground tree biomass was 368.9 kg and the carbon was 215.9 kg which is 58.5% from the biomass. The amount of carbon in the canopy was 64.5% from the canopy dry mass. The carbon percentages of the primary, secondary and tertiary branches and leaves were 61.7, 59.1 and 79.6 respectively. The total above ground tree carbon for a 27 year old P. caribaea plantation was 103.6 T ha-1.Then regression models were developed to identify the relationships of biomass and carbon with stem volume. A relationship between biomass and carbon was also developed for the selected species. Finally, mathematical models were developed to predict biomass and carbon using some other tree variables such as diameter and height, without felling the trees.

Models for estimating Carbon stock in Stem wood biomass of Poplar trees in Agroforestry plantations in Tarai Plains of North-Western India

Poplar (Populus deltoides) based Agroforestry Systems are prevalent in Saharanpur and Yamunanagar districts of North-Western India. These systems are not only remunerative to the farmers but also contributing in CO2 mitigation of environment through biomass accumulation in tree biomass. As stem wood biomass contributes maximum in total tree biomass and no direct method is available for estimating carbon stock in it, some models need to be developed. Primary data on Poplar trees from Agroforestry plantations of different ages was collected from the two districts. Two sets of data, one for boundary system and other for Agrisilvisulture System were used for developing models/equations. Linear and non-linear equations have been developed for carbon stock in stem wood biomass using height and diameter at breast height as explanatory variables. Fitted non-linear equations were found better than linear equations on the basis of adjusted R2 and mean square error for two systems. Thus, developed equations viz., C = -12.288+0.744D+0.139D2 (R2=0.998, MSE=1.219) for boundary system; C = 13.823+0.736D+0.143D2 (R2=0.998, MSE=0.719) for agrisilviculture system; and C = -12.645+0.719D+0.141D2 (R2=0.998, MSE=0.276) for pooled system; where C-carbon stock in stem wood biomass (kg/tree) and D-diameter at breast height (cm) are found good fit. Hence these models/equations may be used for estimating carbon stock in stem wood biomass of Poplar trees in Agroforestry plantations of tarai plains in North-Western India.

Effect of spacing on Biomass production, Nutrient content and uptake by Poplar (Populus Deltoides) plantations

Among exotic tree species, Poplar (Populus deltoides) is a winter deciduous tree species, which produces maximum litter in a single flush for maintaining soil fertility of plantations through its decomposition and release of nutrients and are chosen primarily for their capacity to achieve high growth rates and wood production over a wide range of sites. Besides these, the short rotation cycle of plantation has one major problem of depletion of nutrients that is caused by frequent harvest of plant, which leaves the site unfertile as a huge quantity of nutrients are removed. Keeping these points in view, the present study was conducted to estimate the biomass production and nutrient removal by eight years old Poplar plantation raised at different spacing in a replicated randomized block design having three spacing of 5 x 4 m, 10 x 2.5 m and 15 x 2.5 m in research area of Department of Forestry, C CSHAU Hisar. Biomass of all the plant parts decreased with increasing tree spacing except that the differences between 10 x 2.5 m and 15 x 2.5 m spacing in respect of leaves and branches biomass were not significant. The total tree biomass including litter fall was higher in 5 x 4 m (415 t/ha) followed by 10 x 2.5 m (330 t/ha) and 15 x 2.5 m (192 t/ha) spacing. Concentration of both primary and secondary nutrients in different plant parts differed significantly at different spacing. Maximum nutrient concentration was recorded in leaves at 15 x 2.5 m spacing. However, Poplar stem accounted for maximum uptake of all the nutrients. Among poplar spacing, closer tree spacing of 5 x 4 m recorded maximum uptake of both primary and secondary nutrients except that K and Mg uptake was maximum at 10 x 2.5 m spacing.

General allometric equations and biomass allocation of Pinus massoniana trees on a regional scale in southern China

AbstractApplying allometric equations in combination with forest inventory data is an effective approach to use when qualifying forest biomass and carbon storage on a regional scale. The objectives of this study were to (1) develop general allometric tree component biomass equations and (2) investigate tree biomass allocation patterns for Pinus massoniana, a principal tree species native to southern China, by applying 197 samples across 20 site locations. The additive allometric equations utilized to compute stem, branch, needle, root, aboveground, and total tree biomass were developed by nonlinear seemingly unrelated regression. Results show that the relative proportion of stem biomass to tree biomass increased while the contribution of canopy biomass to tree biomass decreased as trees continued to grow through time. Total root biomass was a large biomass pool in itself, and its relative proportion to tree biomass exhibited a slight increase with tree growth. Although equations employing stem diameter at breast height (dbh) alone as a predictor could accurately predict stem, aboveground, root, and total tree biomass, they were poorly fitted to predict the canopy biomass component. The inclusion of the tree height (H) variable either slightly improved or did not in any way increase model fitness. Validation results demonstrate that these equations are suitable to estimate stem, aboveground, and total tree biomass across a broad range of P. massoniana stands on a regional scale.

Functions for biomass and basic density of stem, crown and root system of Norway spruce (Picea abies (L.) Karst.) in Denmark

Models for predicting the biomass of forest trees are becoming increasingly important for assessing forest resources and carbon sequestration in forests. We developed functions for predicting the biomass and basic density of above- and below-ground parts of Norway spruce (Picea abies (L.) Karst.) in Denmark. Separate models were developed for branches (including foliage), stem and the below-ground stump and root system as well as for the aggregate components of total above-ground biomass and total tree biomass. Trees were sampled in 14 forest stands, reflecting the range of growth conditions and thinning practises of Norway spruce in Denmark. Because of inclusion of experimental plots, data reflected a wider range of thinning practices than commonly used in forestry practice. The data included measurements of biomass and basic density from 114 trees, two of which were regarded as outliers and consequently excluded in the final model estimation. The final models reflected known properties of tree growth and allocation of biomass among different tree components of even-aged Norway spruce. The models were successful in predicting biomass, basic density and biomass expansion factors across a wide variety of tree sizes, stand treatments and growth conditions. The models are believed to substantially improve national estimates of carbon sequestration and biomass resources.